Internet Engineering Task Force (IETF) H.W. Ribbers
Request for Comments: 8063 M.W. Groeneweg
Category: Standards Track SIDN
ISSN: 2070-1721 R. Gieben
A.L.J. Verschuren
February 2017
Key Relay Mapping for the Extensible Provisioning Protocol
Abstract
This document describes an Extensible Provisioning Protocol (EPP)
mapping for a key relay object that relays DNSSEC key material
between EPP clients using the poll queue defined in RFC 5730.
This key relay mapping will help facilitate changing the DNS operator
of a domain while keeping the DNSSEC chain of trust intact.
Status of This Memo
This is an Internet Standards Track document.
This document is a product of the Internet Engineering Task Force
(IETF). It represents the consensus of the IETF community. It has
received public review and has been approved for publication by the
Internet Engineering Steering Group (IESG). Further information on
Internet Standards is available in Section 2 of RFC 7841.
Information about the current status of this document, any errata,
and how to provide feedback on it may be obtained at
http://www.rfc-editor.org/info/rfc8063.
Copyright Notice
Copyright (c) 2017 IETF Trust and the persons identified as the
document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents
(http://trustee.ietf.org/license-info) in effect on the date of
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include Simplified BSD License text as described in Section 4.e of
the Trust Legal Provisions and are provided without warranty as
described in the Simplified BSD License.
Ribbers, et al. Standards Track [Page 1]

RFC 8063 EPP Key Relay February 20171.1. Conventions Used in This Document
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in BCP 14, RFC 2119
[RFC2119].
XML is case sensitive. Unless stated otherwise, the XML
specifications and examples provided in this document MUST be
interpreted in the character case presented in order to develop a
conforming implementation.
In the examples, "C:" represents lines sent by a protocol client and
"S:" represents lines returned by a protocol server. Indentation and
white space in the examples are provided only to illustrate element
relationships and are not mandatory features of this protocol.
1.2. Secure Transfer of DNSSEC Key Material
Exchanging DNSSEC key material in preparation of a domain name
transfer is one of the phases in the life cycle of a domain name
[DNSOP].
DNS operators need to exchange DNSSEC key material before the
registration data can be changed to keep the DNSSEC chain of trust
intact. This exchange is normally initiated through the gaining
registrar.
The gaining and losing DNS operators could talk directly to each
other (see Figure 1) to exchange the DNSKEY, but often there is no
trusted path between the two. As both can securely interact with the
registry over the administrative channel through the registrar, the
registry can act as a relay for the key material exchange.
The registry is merely used as a relay channel. Therefore, it is up
to the losing DNS operator to complete the intended transaction. The
registry SHOULD have certain policies in place that require the
losing DNS operator to cooperate with this transaction; however, this
is beyond the scope of this document. This document focuses on the
EPP protocol syntax.
Ribbers, et al. Standards Track [Page 3]

RFC 8063 EPP Key Relay February 2017
+--------------------+ DNSKEY +---------------------+
|gaining DNS operator| ~~~~~~~~> | losing DNS operator |
+--------------------+ +---------------------+
| ^
| |
V |
+--------------------+ +---------------------+
| gaining registrar | | registrar of record |
+--------------------+ +---------------------+
| ^
EPP key relay | | EPP poll
V |
+-----------------------------+
| registry |
+-----------------------------+
Figure 1: Transfer of DNSSEC Key Material
There is no distinction in the EPP protocol between Registrars and
DNS operators, and there is only mention of an EPP client and EPP
server. Therefore, the term "EPP client" will be used for the
interaction with the EPP server for relaying DNSSEC key material.
2. Object Attributes2.1. DNSSEC Key Material
The DNSSEC key material is represented in EPP by a <keyRelayData>
element.
2.1.1. <keyRelayData> Element
The <keyRelayData> contains the following elements:
o One REQUIRED <keyData> element that contains the DNSSEC key
material as described in [RFC5910], Section 4.
o An OPTIONAL <expiry> element that describes the expected lifetime
of the relayed key(s) in the zone. When the <expiry> element is
provided, the losing DNS operator SHOULD remove the inserted key
material from the zone after the expiry time. This may be because
the transaction that needed the insertion should be either
completed or abandoned by that time. If a client receives a key
relay object that has been sent previously, it MUST update the
expiry time of the key material. This enables the clients to
update the lifetime of the key material when a transfer is
delayed.
Ribbers, et al. Standards Track [Page 4]

RFC 8063 EPP Key Relay February 2017
The <expiry> element MUST contain exactly one of the following child
elements:
<absolute>: The DNSSEC key material is valid from the current date
and time until it expires on the specified date and time. If a
date in the past is provided, this MUST be interpreted as a
revocation of a previously sent key relay object.
<relative>: The DNSSEC key material is valid from the current date
and time until the end of the specified duration. If a period of
zero is provided, this MUST be interpreted as a revocation of a
previously sent key relay object.
3. EPP Command Mapping
A detailed description of the EPP syntax and semantics can be found
in the EPP core protocol specification [RFC5730]. The command
mapping described here is specifically for use in this key relay
mapping.
3.1. EPP Query Commands
EPP provides three commands to retrieve object information: <check>
to determine if an object is known to the server, <info> to retrieve
detailed information associated with an object, and <transfer> to
retrieve object transfer status information.
3.1.1. EPP <check> Command
Check that semantics do not apply to key relay objects, so there is
no mapping defined for the EPP <check> command and the EPP <check>
response.
3.1.2. EPP <info> Command
Info command semantics do not apply to the key relay objects, so
there is no mapping defined for the EPP <info> command.
The EPP <info> response for key relay objects is used in the EPP poll
response, as described in [RFC5730]. The key relay object created
with the <create> command, described in Section 3.2.1 is inserted
into the receiving client's poll queue. The receiving client will
receive the key relay object using the EPP <poll> command, as
described in [RFC5730].
Ribbers, et al. Standards Track [Page 5]

RFC 8063 EPP Key Relay February 2017
When a <poll> command has been processed successfully for a key relay
poll message, the EPP <resData> element MUST contain a child
<keyrelay:infData> element that is identified by the keyrelay
namespace. The <keyrelay:infData> element contains the following
child elements:
o A REQUIRED <name> element containing the domain name for which the
DNSSEC key material is relayed.
o A REQUIRED <authInfo> element that contains authorization
information associated with the domain object ([RFC5731],
Section 3.2.1).
o One or more REQUIRED <keyRelayData> elements containing data to be
relayed, as defined in Section 2.1. A server MAY apply a server
policy that specifies the number of <keyRelayData> elements that
can be incorporated. When a server policy is violated, a server
MUST respond with an EPP result code 2308 "Data management policy
violation".
o An OPTIONAL <crDate> element that contains the date and time of
the submitted <create> command.
o An OPTIONAL <reID> element that contains the identifier of the
client that requested the key relay.
o An OPTIONAL <acID> element that contains the identifier of the
client that SHOULD act upon the key relay.
Example <poll> response:
Ribbers, et al. Standards Track [Page 6]

RFC 8063 EPP Key Relay February 20173.1.3. EPP <transfer> Command
Transfer semantics do not apply to key relay objects, so there is no
mapping defined for the EPP <transfer> command.
3.2. EPP Transform Commands
EPP provides five commands to transform objects: <create> to create
an instance of an object, <delete> to delete an instance of an
object, <renew> to extend the validity period of an object,
<transfer> to manage object sponsorship changes, and <update> to
change information associated with an object.
3.2.1. EPP <create> Command
The EPP <create> command provides a transform operation that allows a
client to create a key relay object that includes the domain name and
DNSSEC key material to be relayed. When the <create> command is
validated, the server MUST insert an EPP <poll> message, using the
key relay info response (see Section 3.1.2), in the receiving
client's poll queue that belongs to the registrar on record of the
provided domain name.
In addition to the standard EPP command elements, the <create>
command MUST contain a <keyrelay:create> element that is identified
by the keyrelay namespace. The <keyrelay:create> element contains
the following child elements:
o A REQUIRED <keyrelay:name> element containing the domain name for
which the DNSSEC key material is relayed.
o A REQUIRED <authInfo> element that contains authorization
information associated with the domain object ([RFC5731],
Section 3.2.1).
o One or more REQUIRED <keyrelay:keyRelayData> elements containing
data to be relayed, as defined in Section 2.1.
Ribbers, et al. Standards Track [Page 8]

RFC 8063 EPP Key Relay February 20175. IANA Considerations5.1. XML Namespace
This document uses URNs to describe an XML namespace conforming to
the registry mechanism described in [RFC3688]. The following URI
assignment has been made by IANA:
URI: urn:ietf:params:xml:ns:keyrelay-1.0
Registrant Contact: See the "Authors' Addresses" section of this
document.
XML: See the "Formal Syntax" section of this document.
5.2. XML Schema
This document uses URNs to describe an XML schema conforming to the
registry mechanism described in [RFC3688]. The following URI
assignment has been made by IANA:
URI: urn:ietf:params:xml:schema:keyrelay-1.0
XML: See the "Formal Syntax" section of this document.
5.3. EPP Extension Registry
The EPP extension described in this document has been registered by
IANA in the "Extensions for the Extensible Provisioning Protocol
(EPP)" registry described in [RFC7451]. The details of the
registration are as follows:
Name of Extension: "Key Relay Mapping for the Extensible Provisioning
Protocol"
Document status: Standards Track
Reference: RFC 8063
Registrant Name and Email Address: IESG, iesg@ietf.org
Top-Level Domains (TLDs): Any
IPR Disclosure: https://datatracker.ietf.org/ipr/
Status: Active
Notes: None
Ribbers, et al. Standards Track [Page 13]

RFC 8063 EPP Key Relay February 20176. Security Considerations
A server SHOULD NOT perform any transformation on data under server
management when processing a <keyrelay:create> command. The intent
of this command is to put DNSSEC key material on the poll queue of
another client. Exceptions to this recommendation are allowable only
for the purposes of achieving interoperability with the different
server policies that have already implemented this EPP extension.
Any EPP client can use this mechanism to put data on the message
queue of another EPP client, allowing for the potential of a denial-
of-service attack. However, this can and should be detected by the
server. A server MAY set a server policy that limits or rejects a
<keyrelay:create> command if it detects that the mechanism is being
abused.
For the <keyrelay:keyRelayData> data, a correct <domain:authInfo>
element should be used as an indication that putting the key material
on the receiving EPP clients poll queue is authorized by the
_registrant_ of that domain name. The authorization of EPP clients
to perform DNS changes is not covered in this document as it depends
on registry-specific policy.
A client that uses this mechanism to send DNSSEC key material to
another client could verify through DNS that the DNSSEC key material
is added to the authoritative zone of the domain. This check can be
used to verify that the DNSSEC key material has traveled end-to-end
from the gaining DNS operator to the losing DNS operator. This check
does not tell anything about the DNSSEC chain of trust and can merely
be used as a verification of a successful transfer of the DNSSEC key
material.
Ribbers, et al. Standards Track [Page 14]